SEL RTAC Troubleshooting and Diagnostics
Key Takeaway
How to diagnose RTAC issues — protocol communication faults, BAD tag quality, IEC 61131-3 program errors, deploy failures, time sync problems, and HMI access issues.
Quick Answer
Start with the RTAC event log and protocol driver diagnostics in ACSELERATOR RTAC online mode. Common issues: BAD tag quality (source device communication lost), protocol address mismatches, deploy failures (firmware mismatch), and time sync loss.
Protocol Faults
- SEL protocol no data — Check baud rate, COM port, relay password, serial cable
- DNP3 no response — Check outstation address, IP/port, firewall port 20000
- Modbus timeout — Check IP, port 502, unit ID, use Modbus Poll to test independently
- IEC 61850 GOOSE missing — Wireshark capture, verify AppID/GoID, check VLAN tagging
BAD Tag Quality
Identify source protocol driver → check driver diagnostics → verify field device is powered and communicating → check physical/network path.
Program Faults
- Build errors: syntax errors in ST or Ladder
- Runtime: divide by zero, array out of range
- Task overrun: program exceeds cycle time
Deploy Failures
Most common: firmware version mismatch, duplicate port assignments, license validation. Check deploy log for specific errors.
See also SEL relay troubleshooting and Modbus troubleshooting.
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Frequently Asked Questions
In ACSELERATOR RTAC online mode, each driver's diagnostics panel shows connection state, last poll time, message counters, and errors.
The protocol driver lost communication with the source device — serial cable failure, device power loss, network path failure, or address mismatch.
Check the deploy log for specific errors. Most common: firmware mismatch (update hardware firmware or change project target), duplicate port assignments, or license issues.
Still have questions about your setup? Talk to an engineer or call (210) 405-4248.